Preparation of a reddish derivative of flavanthrone



Oct. 28, 1930 a. WYLAM ET AL 1,779,791

PREPARATION OF A REDDI'SR DERIVATIVE 0F FLAVANTHRONE Filed April 19, 1926 I igz rwf Patented Oct. 28, 1930 i -VUNITEDYVSTATES "PATIENT; A 1

3131mm *WYLAM, or LANCASTER, AND JOHN, EDMUND quiz-H RRIS, or" GARLISLE,

ENGLAND, AND JOHN THOMAS, or GRANGEMOUTH, SCOTLAND, ASSIGNORS T0 soo'r- .1 Y ,"IISH DYES, LIMITED, 01 GRANGEMOUTH,scoTLANn;

VPREPABATION or A REDDISH nnnrvA'rivn or FLAVANTHRONE.

Application 111611 April 19, 1926; Serial No; 103,133, and in Great Britain A ril 30,1925.

7 This invention relates to the art of-dyeing and to the production of dyes. v i i The object of'the'present invention is to i provide improvedor modified flavanthrone derivatives or'improvedor modified methods of making flavanthronederivatives.

The invention inbrief consists in a process for producing a reddish fiavanthrone'd'erivative comprising the treatment of leucoflavanthrone with an alkyl sulphuric-acid halide, for example methyl sulphuric acidv chloride at temperatures above about (3.,

in the presence of a tertiary organic base.

ing parts by weight The accompanying diagram illustrates what appears to be the structure of the reddish de-.

rivative of flavanthrone prepared as hereindescribed. 7 a -""The following examples illustrate several methods of carryingthe invention into -ef-* fect, all parts unless otherwise specified be- 7 .5 partsof methyl sulphuric acid chloride are added with stirring and good-cooling to 1 8? partsfojf dry light pyridine. (lower fractions of pyridineliquors obtained incoaltar distillation, .of vWhich a typical example ,is 90/140 pyridine,th'at, is" to say, a pyridine of which90"% distils below'140" G.) con tained ,in anafpparatus in which there is'a'n atmosphere 0 carbon dioxide.

tying the flavanthrone vatand drying the preclpitate in an inert: atmosphere) are now added to the mixture. 5 Thetemperature is nowfraised1to in the course of about half anhour and kept at 60? for a'fur ther half hour.', The yellowish red melt is now a I 3.pajrtsvof dry leuco-flavanthrone :(prepared by acidi- V aqueous solution of ammonia gas of specific gravity 0.880and containing approximately 34% of .ammoniafby Weight), whereby a reddish solid is partlyprecipitated. vThis may solution, under -which conditions the dicipitated which dissolves in waterto form beused directly for dyeing in faintly alkaline a deep orangered solution that dyes cotton andrwool from a. slightly alkaline" bath a i brilliant'scarlet colour, which 'is' developed to yellow bymeansof acidoxidi-zing agents.

This derivative appears totbe the disodium salt of the di-sulphuric acid' ester of leuco fiavanthrone.

"Beam/1 2k i I i This 'to leucolflavanthrone and chlor-sulphonic acid. v

To 3 0 parts of pyridine cooled in ice and well 'stii'rd 'are slowly added 10'.5',parts of chlor-sulplionic acid. To the mixture are now added 3 parts of dry leuco-flavanthrone.

tained for analysis was not pure. It is, however, possible to synthesize the dimethyl pyridinium derivative of the disulphuric acid ester *of' leuco' fiavanthi'one by? treatiagalie disodium salt of the disulphurie acid-Tester The temperature israised to. 45f and kept at...

this for 40 minutes; The cooled melt is then added to12O0 parts1of :water 'containingjpllw.

parts of 0.880 ammonia. .The precipitated "solid is filtered off andjdissolved in 1 per centisodiurn' carbonate solution. A bright red solution is obtained rro which a reddish yellow solid may be. separated by the addition ofxcommon salt." The reddish yellow solid thusv precipitated is apparently the disodiumlsaltof the disulphuric acid? ester "of. leuco flavanthrone, the propertiesofwhich havebeen described above Example ;1. Some unconverted leuco compound may also be extracted by the sodiunicarbonate. lhis may be removed by aeration prior to salting out. '"Small amounts ofabluesubstance, less stable than the red 'body',1'may alsob'e produced.' This is less soluble-than the' red subfstance in dilute SQdlUIliJCJfbODatBJ It also oxidizeson standing' n the lighta-ndiin contact with air and converted to 'an insoluble substance (apparently flavanthrone) which maybe removed by filtration/ LThe. reddish derivatives of flavanthrone prepared as herein I described "may its; em- 'pl'oyed for dyeing without the use of vats and suitable textile fibres or' the like."

(1 "l he productsoriginally presentin the 'leuco compound and theesterifying agent.

1(2) The-product towhich these substances i areconverted the action'ofaqueous alkali.

' ple 1' andobtain'ed when the' yellowish" red I The product presentin thef melt of Exammelt is poured into water containing ammonia, as describedisaccording to our tests a dimethyl pyridinium derivative of the disulphuric .acid ester of leuco flavanthrone. Owing to the instability of this' sub'stance, it is liabl'eto undergo decomposition during the processes-necessary for its isolation from the melt and separation from accompanying impurities so that it is diflicult to obtain accurate analyses. Typical .figures ,which have been obtained are as.foll0ws;.

3.45 atoms of nitrogen tolmolecule of flavanwith methyl pyridiniumiodide? Tlie substance. thus obtained. may. be analyzed, yielding the figuresgiven-below. Further, it may llGiISllOWIl' by qualitativeitests-ito beridentical with the crudeproduct obtained fromthe melt as describedjabove; which is thus shown to be, in the main the-dimethyl pyridinium derivativeIofxthe. disulphuric acid ester of v The fanalytical fig- 'ures obtained from this synthetic preparationare as iolloWs:..

' 1 a Per cent 'Expi'essed'in another way, 1 molecule of "flavanthr'one is associated with 1.97 atoms R A a k 7. Per cent Flavanthrone a; 50.64 Sulphur.. 6.4

' l litrogen f 5.97

giving-a vratio of 1154 atoms of sulphur and throne, showing that the substance as ob- 1;

of sulphurand 2.09 atoms of additional 'nitrogen, the total nitrogenrcontent of the derivative being,4.09 atoms oiinitrogen, which result would agree withthe view that the prodnot is a disulphuric acid ester,and that it is also the dimethylpyridi-nium salt.

In a .sim i-larmw ay the crude-product obtained from the melt of Example 2 by adding the melt to aqueous ammonia may be' shown to beimainly the pyridiniuin'salt of the disulphuric. acid ester of leuco fiavanthrone.

. The samegdifiicultie's are encountered in obtainingaccurate,analyses of the .crude product ioo of the melt; but this may be shown by various I qualitative tests tome-identical with the dipyridini'un -s'alt of the disulphuric acid ester of flavanthrone which maybe obtained by treating the disodiu'm salto f the disulphuric acidester with pyridine hydrochloride in the.

presence of excessfiplyridine. The substance so prepared on analysis was found to contain This'corresponds to about 6 molecules of Water of crystallization. Y

The calculated composition forl dangmloss cngo Percent Flavanthroney 48..8

In the examples shown the crude products of the melt are eventually extracted by Warm aqueous alkali, for example 1 5% sodium carbonate, whereby the methyl pyridinium and pyridinederivatives described above are converted to the corresponding sodium salt, which are in most cases the mostusetul forms in which the products may be employed for dyeing.

In order to determine the constitution of these substances the freshly prepared pastes, obtained by extracting the crude condensation product with soda ash, followed by subsequelt salting out of the product, was examme A given quantity of the paste was treated with a small excess of concentrated hydrochloric acid which decomposes the red product to a bluish-green substance. This was immediately filtered ofl and the sulphuric acid in the filtrate was determined. The bluish-green substance was then pasted up with a water and sodium nitrate and dilute hydrochloric acid added, when flavanthrone was precipitated. This was filtered off and estimated. The sulphuric acid present in the filtrate was determined.

Theseresults showed that in the decomposition of the red salt to the bluish-green sub-,

stance 1.06 molecules of. sulphuric acid were liberated and in the conversion of the green substance by acid oxidation to flavanthrone 0.9 molecules of sulphuric acid were liberated for 1 molecule of flavanthrone, that is,.the

product may be regarded as a disulphuric acid ester of flavanthrone, viz., the sodium salt, approximate analysis givinga ratio of 1.7

atoms of sodium to 1 molecule of flavanthrone. I

' Having now described our invention what we claim as new and desire to secure by Letters Patent is 1. A method for producing a reddish derivative of flavanthrone which consists in treating leuco flavanthrone at a temperature above about 50 C. and in the presence of a tertiary organic base with a reagent selected from the following, namely an alkyl sulphuric acid halide, and then extracting the melt with a dilute alkali.

2. A process for producing a reddish derivative of flavanthrone which consists in the treatment of leuco flavanthrone in suspension in a liquid tertiary organic amine with an alkyl sulphuric acid halide and extraction of the resultant melt with dilute alkali.

'3. A process for the production of a reddish derivative of flavanthrone which consists in treating leuco flavanthrone at a temperature above about 50 C. in the presence of a liquid tertiary organic base with an alkyl sulphuric acid halide and extracting the melt with a dilute alkaline solution.

4. A method for producing a reddish detreating leuco flavanthrone at'a temperature above about 50 C. in the presence of a liquid tertiary'organic base with methyl sulphuric acid chloride and extracting the melt with a dilute alkali;

5. Aprocess'forproducing a reddish flavanthrone derivative which comprises the admixture of an alkyl sulphuric acid halideand a liquid tertiary organic base .and the subsequent addition to this mixture of leuco flavanthrone after which the temperature is raised to above about 50 C. and the product extracted by a dilute alkaline-solution.

6. A process for producing a reddish flavanthrone derivative comprising the treatment of leuco flavanthrone with an alkyl sulphuric acid halide inthe presence of an amount of a liquid tertiary organic base in excess of the quantity corresponding to one molecule of liquid tertiary organic base per molecule of alkylsulphuric acid halide at a temperature of above about 50 C. and extraction of the product by a dilute alkaline solution. I

7 A process for producing a reddish fla vanthrone derivative which comprises the admixture of methyl sulphuric acid chloride and pyridine and the subsequent addition to this mixture of leuco flavanthrone after which the temperature is raised to above about 50 C. and subsequently the crude product is extracted by a dilute solution of a sodium salt. 0

84A reddish derivative of flavanthrone soluble in water forming a deep orange-red solution and dyeing cotton and wool from a slightly alkaline bath a brilliant scarlet colour which is developed to yellow by means of acid oxidizing agents, this derivative being such as may be prepared by theaction of a sulphuric acid halide on leuco flavanthrone in the presence of a liquid tertiary organic base and the product extracted with a dilute alkaline solution.

rivative of flavanthrone which consists in a v & 

